Wireless communication signals sent between wireless communication devices or between a wireless communication device and the communication infrastructure are susceptible to jamming signals. More particularly, a desired signal, or signal of interest, is a signal that conveys information, such as audio, video, text or other media or control information between two or more devices over a physical transmission medium. A jamming signal is any signal that disrupts or interferes with the reception of a desired signal by, for instance, decreasing a signal-to-noise ratio for the desired signal.
Typically, the jamming signal transmission occupies the same frequency and has the same modulation type as the desired signal, and the jamming signal has enough signal power to impede or altogether block reception of the desired signal. The signal-to-noise ratio measures a signal level (also referred to herein as “signal power” or “signal strength”) of a desired signal as compared to the signal level of noise or any other undesired signal. Where signal-to-noise ratio is low (such as less than one), a receiving device of desired signals is less likely to be able to discern the desired signals from undesired signals. Accordingly, desired signals are not properly received and processed by the receiving device, and the wireless communication with the receiving device is thus disrupted or even disabled.
A device that generates or transmits jamming signals is termed, herein, as a jammer or jamming device. For example, a radio jamming device disrupts a wireless communication by transmitting radio frequency signals (also referred to herein simply as “radio signals” or “signals”) in the same radio frequencies (also referred to herein simply as “frequencies”) being used by wireless communication devices transmitting desired signals. Radio signals are carried over radio waves that have frequencies (i.e., rates of oscillation), within the radio spectrum, ranging from hundreds of gigahertz to as low as a few hertz. The entire spectrum of radio frequencies is divided into multiple smaller frequency ranges, known in the art as radio frequency bands (frequency bands or bands for short). Oftentimes, each frequency band is further divided or allocated into multiple radio channels (also referred to herein as “channels”). A channel is, accordingly, defined herein as a portion of a frequency band within the electromagnetic spectrum (for example within the radio spectrum) that is allocated and used to carry desired signals and is often characterized at least by a receive or transmit frequency and a capacity, which is often measured by the channel's bandwidth (e.g., in Hz) and/or data rate (e.g., in bits per second). As used herein, bandwidth is the difference between upper and lower frequencies in a continuous set of frequencies, and data rate is the maximum rate at which information can be passed over the channel.
Radio jamming devices are known to transmit a jamming signal over a single radio channel (meaning the jamming signal is transmitted using just the bandwidth of the single radio channel) or a small portion of radio frequencies of a radio frequency band. In such a case, the jamming signal is termed herein as a narrowband jamming signal, where the bandwidth of the jamming signal is less than or equal to the bandwidth of a desired signal that can be transmitted over the same radio frequency band. However, some radio jamming devices transmit a jamming signal over some or all radio channels within one or more radio frequency bands. Accordingly, in such a case, the jamming signal is referred to herein as a broadband jamming signal, where the bandwidth of the jamming signal is larger than the bandwidth of a desired signal that can be transmitted over the same radio frequency band. Such broadband jamming signals can disrupt or even block usage of the same channels by communication devices attempting to transmit desired signals.
Accordingly, there is a need for methods and apparatus for detecting presence of a jamming signal, including a broadband jamming signal.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. It will be further appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.
Apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the various embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.